When a silver halide light-sensitive material is exposed to lights containing light rays to which the light-sensitive material responds and then developed, the light-struck portions acquire black density which increases as the exposure amount increases to reach its maximal value. However, as the exposure amount is further increased, the black density again decreases to finally form a positive image. This phenomenon is generally called solarization. The same reversal phenomenon takes place with silver halide having been optically or chemically fogged in the course of the steps of preparing a silver halide emulsion containing it. The direct reversal silver halide photographic emulsion used in this specification means an emulsion which has been optically or chemically fogged so as to provide a positive image after ordinary exposure to light and ordinary development.
These types of direct reversal silver halide photographic light-sensitive materials are being used for copying various photographs. In photographic plate-making processes, they are often used, in a step called "reversing", for printing an original halftone dot image positive to positive or negative to negative. Photographic light-sensitive materials to be used in this reversing step must be handled under safe light. Various photographic light-sensitive materials capable of being handled under orthochromatic and panchromatic safe lights are known. Under such safe light, however, workability is poor, and the plate-making step is costly. Therefore, in recent years photographic light-sensitive materials usable under a visible safe light (safe light emitting light rays of mainly 450 nm or longer in wavelength) have been developed (hereinafter referred to as photographic light-sensitive materials for a bright room).
With direct reversal silver halide photographic light-sensitive materials, however, techniques for converting them to the type usable in a bright room have not yet been established. Thus, insufficient resistance to a visible safe light has often caused undesirable phenomena in plate-making processes such as reduction of maximum density, undesirable change in halftone dot area, etc.
That is, in order to make photographic light-sensitive materials handlable in a bright room, it is possible to add a filter dye to an emulsion layer of light-sensitive material or to a hydrophilic colloid layer provided on or above the emulsion layer. However, conventionally proposed filter dyes (for example, oxonol dyes as described in British Pat. No. 506,385, U.S. Pat. Nos. 3,247,127, 2,533,472, 3,379,533, British Pat. Nos. 1,278,621, etc., styryl dyes as described in U.S. Pat. No. 2,298,733, merocyanine dyes as described in U.S. Pat. No. 2,493,747, cyanine dyes as described in U.S. Pat. No. 2,843,486, arylidene dyes as described in British Pat. Nos. 584,609, 900,094, French Pat. No. 1,350,311, U.S. Pat. No. 3,540,887, Japanese Patent Application (OPI) No. 40625/75, etc., and the like) have disadvantages. The term "OPI" as used herein refers to a "published unexamined Japanese patent application". For example, some fail to impart sufficient visible safe light properties to direct reversal silver halide photographic light-sensitive materials, some cause an extreme reduction in intrinsic sensitivity, some cause serious residue of color (residue of the dye in light-sensitive materials after photographic processing), and some decompose during production or storage.